"Any guesses what it's used for?"
"Well it would definitely affect brain chemistry, so it could be used as some kind of a drug or stimulant I suppose."
Terrazine gas is a mysterious potent psionic reagent. It is sought by protoss, zerg and terrans alike. The protoss consider it "the Breath of Creation" (literally translates as such via Khalani). The Tal'darim believe that terrazine is a gift from the xel'naga to allow communication with them.
Terrazine is similar to vespene gas, and contains additional organic substances, though is not as flammable. Without special preparation and containers, samples don't last long. Visually, terrazine has appeared to be purple and misty green.
Terrazine has a coppery, blood-like smell.
Biological and PsychologicalEdit
Its effects are unpredictable, though it possesses mind-altering qualities and can enhance the psionic power of ghosts and other psychics, increasing their power by 1 or more points on the Psi Index scale, though the effects would probably not be noticable on an individual possessing an average PI. Gabriel Tosh believed this could increase a ghost's powers to near those of the protoss. Terrazine also rejuvenates a terran's brain cells, allowing them to overcome memory wipes and other such treatments. At least some spectres can also more easily resist mind-reading and can avoid picking up unwanted thoughts.
Terrazine's side effects include hallucinations and violent outbursts. The exact effects vary somewhat from one individual to another. Many spectres became eccentric, collecting devices such as dolls in an effort to enhance their powers.
Nova Terra claimed that terrazine drove the users insane, and the instability resulted in the shutdown of Project Shadowblade. Tosh and an independent researcher, Dr. Ariel Hanson, said that Terra had exaggerated its effects.
Terrazine has a half-life of several hours, but it builds up in the system over time and with repeated use. It is addictive, causing withdrawal symptoms after several hours. Stabilized by a little jorium, terrazine is inhaled by spectres like a drug. If the spectre keeps to a strict schedule, the side effects are minimized.
The Second Great WarEdit
During the Second Great War, Gabriel Tosh commissioned Raynor's Raiders to steal terrazine from protoss altars on Bel'Shir. The altars were guarded by the Tal'darim, who regarded the gas as a sacred gift from the xel'naga, and refused to give the terrans any. The Raiders took what they needed by force.
This article or section contains information about StarCraft: Ghost, which has been declared non-canon. Elements may be taken as 'flavor lore' however.
Mar Sara featured a Dominion-operated "Vespene" Refinery BF 1138, a terrazine refinery on Mar Sara, disguised as a vespene refinery, which was infested by zerg and had to be rescued by Nova (a ghost) and other Dominion forces.